The Rpc Server Is Unavailable Microsoft Word

I am using a COM Interop and i am instantiating the COM class object from the interop dllSo, few times the object is instantiated successfully and make remote procedure calls without any problem but sometimes it throws an exception like RPC Server is unavilable.The COM Component i am using is written in VB and i am consuming that component in c#.So, can anybody tell me the possible reasons for the problem(RPC Server is Unavailable) and solutions to this problem.I am helpless with this issue by now.So, Advance thanks if you can help me out.

0x6ba The Rpc Server Is Unavailable

IntroductionRemote Procedure Call (RPC) is an inter-process communication technique to allow client and server software to communicate on a network. The RPC protocol is based on a client/server model.

The client makes a procedure call that appears to be local but isactually run on a remote computer. During this process, the procedure call arguments are bundled and passed through the network to the server. The arguments are then unpacked and run on the server. The result is again bundled and passed back to the client,where it is converted to a return value for the client's procedure call.RPC is used by several components in Windows Server, such as the File Replication Service (FRS), Active Directory Replication, Certificate services, DCOM, domain join, DCPromo and RDP, NLB and Cluster, Microsoft Operations Master, Exchange and SQL.